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Improperly Controlled Modification of Object Prototype Attributes ('Prototype Pollution')


Severity High
Score 9.8/10


Underscore.deep is a collection of Underscore mixins that operate on nested objects. Versions of `underscore.deep` prior to version 0.5.3 are vulnerable to a prototype pollution vulnerability. An attacker can craft a malicious payload and pass it to `deepFromFlat`, which would pollute any future Objects created. Any users that have `deepFromFlat` or `deepPick` (due to its dependency on `deepFromFlat`) in their code should upgrade to version 0.5.3 as soon as possible. Users unable to upgrade may mitigate this issue by modifying `deepFromFlat` to prevent specific keywords which will prevent this from happening.

  • LOW
  • HIGH
  • NONE
  • NONE
  • HIGH
  • HIGH

CWE-1321 - Prototype Pollution

Prototype pollution is one of the lesser-known vulnerabilities. It allows attackers to abuse the rules of JavaScript by injecting properties into the general object “Object” in JS. Modifying the prototype of “Object” affects the behavior of all objects in the entire app, potentially resulting in denial of service, arbitrary code execution, cross-site scripting, etc.


Advisory Timeline

  • Published